Method of preparing printing plates



' Jam. 22, 1924. 1,481,367

H. A. HERR METHOD OF PREPARI NG PRINTING PLATES Original Filed Jan. 2, 1923 2 Sheets-Sheet 1 Jane 22, 1924. 1,481,357

H. A. HERR METHOD OF PREPARING PRINTING, PLATES Original Filed Jan. 2, 1923 2 Sheets-Sheet 2 Patented Jan. 22, 1924.

UNITED STATES PATENT OFFICE.

HENRY A. HERB, OF CHICAGO, ILLINOIS.

METHOD OF PREPARING PRINTING PLATES.

Original application filed January 2, 1923, Serial No. 610,212. Divided and this application filed March 17, 1923. Serial No. 625,701.

To all whom it may concern:

Be it known that I, HENRY A. HERB, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Methods of Preparing Printing Plates, of which the following is a specification. L

his application is a division of my OIlgl nal application, Serial No. 610,212, filed January 2, 1923, and one of'the objects of the presentinvention is to provide an im proved method of preparing a printing plate by the use of the matrix, constituting the subject matter of the above referred to application.

The present invention has for a. further object the use of such a matrix for raising the solid portions of the printing plate by operating from the back of the printing plate so that the solids on the printing surface will be elevated the desired height above the high lights or portions of the surface which are to be printed lighter than the solid portions, and at the same time obviate the danger of marring or injuring the printing surface of the plate.

To the attainment of these ends and the accomplishment of other new and useful objects as will appear, the invention consists in the features of novelty in substantially the herein described method of treating the printing plate as shown in the. accompanying drawings illustrating a method or process of carrying this invention into operation.

In the drawing Figure 1 illustrates the face of the printing or electrotype plate, which is to be treated with this improved method or process.

Figure 2 is a view of the obverse face of the matrix.

Figure 3 is a sectional view on Figure 1.

Figure 4 is a view of the reverse face of the matrix.

Fi re 5 is a sectional View of the matrix, whic is etched on both sides.

line 3----3,

Figure 6 is a sectional View of the printing plate with the matrix placed against the back thereof.

Figure 7 is a sectional view of the printing plate with the matrix applied to the back thereof and the face of the printing plate resting against a body or cushion.

Figure 8 is a sectional view showing the operation of forcing the matrix into the back of the printing plate.

Figure 9 is a view of the completed printing plate, after the back thereof has been smoothed.

In carrying this improved method into operation a relief or electrotype plate is employed having upon its front a picture or reproduction produced in any manner or by any process, certain portions of which designs or reproduction constituting high lights or portions to be printed light and other portions which constitute what is technically known as solids" and which solids are to be printed heavier or darker than the high light portions.

In the drawings, the numeral 15 designates a printin )late such as an electrotype or other suita )le plate having produced upon its face in any ordinary and wellknown manner the design or pattern 16 from which reproductions are to be made.

This design or pattern consists of portions 17 technically known as solids and which portions are to be printed heavier than other portions 18, technically known as high lights, it being understood that.

in the drawings the various figures are illustrated on an exaggerated scale.

In carrying this improved method into operation, a matrix 19 is prepared in the manner as set forth in the application herein referred to, that is to say the matrix has etched on both faces thereof facsimiles of the design appearing in the face of the printing plate 15, so as to produce or form elevations 2t) and depressions 21 on both faces thereof, the elevations .20 corresponding with the solids on the face of the printing plate and the depressions 21 corresponding'to the high lights portion or port-ions on the printing plate-which are printed lighter than the solids.

This matrix is then placed against the back or reverse face of the printing plate 15, so that the depressions 21 will register with the high light port-ions 18 of the plate 15'and the elevations 20 will register with the solid portions 17 of the printing plate 15.

The superposed plates are arranged upon a suitable mat 22, sothat the printing sur face of the plate 15 contacts with the mat. The mat rests upon a suitable support 23 and pressure is brought to bear upon the matrix 19 by means of a suitable plunger 24 With a mat 25 interposed between the plunger and the matrix 19 to force the matrix into the back of the printing plate 15.

This operation will cause predetermined portions of the'printing surface of the printing plate to be displaced by the matrix to cause the solid portions of the printing surface to stand higher than the high light portions so that when transfers or impressions are made by the printing plate, the solids of such plate will print heavier than the high light portions.

The matrix is then removed and the back of the printing'plate is smoothed in any ordinary and well'knownmanner as shown in Figure 9, thereby adapting the plate-to be mounted either upon a block or a bed or cylinder of a printing press.

With this improved method it will be manifest that the heretofore expensive made ready operation is dispensed with and the amount of labor necessary to cause the solid portions on the face of the printing surface to stand higher than the high 95 light portions is materially reduced. Furprinting plate,

thermore, the operations of treating the printing plate are performed from the back' attach the'same to the bed of the press With:

out having to indulge in the laborious undertaking of preparing a make ready on his press.

lVhat is claimed as new is The method of treating printing plates which consists in placing against the back of the plate a matrix which has etched on both -faces thereof registering facsimiles of the design appearing on the face of the printing plate and in a position that the designs on both faces of the matrix will register with the design on the face of the and then applying pressure upon the matrix to displace predetermined portions of the printing surface of the said plate and fromv the back of said plate.

In testimony whereof I have signed my "name to this sp)ecification, on this 14th day of March, A.

HENRY A. HERR. 

